The present invention relates to a substrate holding apparatus for holding a substrate such as a wafer in semiconductor manufacturing, an exposure apparatus for exposing a pattern of a master such as a mask onto a substrate held by the substrate holding apparatus, a device manufacturing method using the exposure apparatus, and a maintenance method for a semiconductor manufacturing factory and an exposure apparatus.
A conventional wafer chuck and exposure apparatus are disclosed in, e.g., Japanese Patent Laid-Open No. 10-223520. FIG. 13 shows the schematic arrangement of the wafer chuck disclosed in this prior art. Referring to FIG. 13, reference numeral 101 denotes a wafer chuck main body; and 107, a wafer. The wafer chuck main body 101 is mounted on a wafer stage (not shown) in an exposure apparatus.
The wafer chuck main body 101 has a wafer holding surface 101a which chucks the wafer 107. In addition, an internal pipe 101d serving as a temperature adjusting fluid path is formed to cause a temperature adjusting fluid to flow for adjusting the temperature of the wafer 107. Water is generally used as a temperature adjusting fluid that flows through the internal pipe 101d. The temperature of this water is controlled by a temperature adjusting unit (not shown).
Chuck grooves 101b are formed on the wafer holding surface 101a of the wafer chuck main body 101. When the chuck grooves 101b are evacuated by a vacuum pump connected to a through hole 101c, a vacuum chucking force that causes the wafer 107 to stick to the wafer holding surface 101a of the wafer chuck 101 is generated.
Recently, micropatterning of circuit patterns is making progress in order to improve the integration degree and operation speed of a solid element such as an LSI. To do this, the gap setting accuracy between the mask and the wafer in a one-to-one X-ray exposure (Proximity X-ray lithography) scheme or the auto-focus (AF) accuracy to the wafer in a reduction projecting exposure scheme must be increased.
An electrostatic capacitance sensor can be used for measuring the height of a wafer held by a wafer chuck. However, the performance of the sensor cannot be sufficiently obtained, because the wafer chuck is made of ceramic, which is a dielectric material. If the performance of the electrostatic capacitance sensor cannot be sufficiently obtained, the AF accuracy or gap setting accuracy degrades. As a consequence, the exposure transfer accuracy, e.g., the imaging performance or overlay accuracy degrades. In the one-to-one X-ray exposure scheme, if the gap setting accuracy degrades, a mask and wafer opposing each other may come into contact with each other, or the mask may be damaged during step-and-repeat operation.
The present invention has been proposed to solve the conventional problems, and has its object to provide a substrate holding apparatus which improves the AF accuracy or gap setting accuracy by improving the measurement accuracy of an electrostatic capacitance sensor, or to provide an exposure apparatus in which the exposure transfer accuracy are improved by improving the AF accuracy or the gap setting accuracy.
In order to achieve the above object, a substrate holding apparatus of the present invention comprises a nonconductive holding section which holds a substrate, wherein the holding section has a conductive member which is electrically grounded.
Preferably, the holding section which holds the substrate has the conductive member on a surface on an opposite side of a surface which holds the substrate.
More preferably, the holding section has a plurality of pins to hold the substrate.
More preferably, the conductive member has a thickness smaller than a height of the pins, and the pins hold the substrate while separating the substrate from the conductive member.
More preferably, the holding section has a plurality of members divided in a predetermined direction, at least one of the plurality of members having the conductive member.
More preferably, the predetermined direction is a direction of thickness of the holding section.
More preferably, at least one of the plurality of members has a channel for a fluid which adjusts a temperature of the holding section.
More preferably, the holding section has the conductive member on a side surface portion.
More preferably, the conductive member is formed by depositing chromium.
More preferably, the conductive member is formed by plating.
More preferably, the conductive member is one of a metal plate and a metal foil.
In the substrate holding apparatus of the present invention, the measurement accuracy by the electrostatic capacitance sensor can be increased.
Further, an exposure apparatus of the present invention comprises the following arrangement.
That is, an exposure apparatus for exposing a pattern of a mask onto a substrate, comprises an apparatus which includes a nonconductive holding section to hold the substrate and holds the substrate; and an electrostatic capacitance sensor which measures height-direction information of the substrate held by the apparatus which holds the substrate, wherein the holding section includes a conductive member which is electrically grounded.
Preferably, the apparatus further comprises a calibration section which executes calibration of the electrostatic capacitance sensor.
More preferably, the calibration section comprises a light source section which makes light incident on an entry window formed in the mask, and a sensor which detects light that becomes incident from the entry window, is reflected by the substrate, and exits an exit window formed in the mask.
More preferably, the apparatus further comprises an interface connected to a network, a computer which executes network software to data-communicate maintenance information of the exposure apparatus through the network, and a display which displays the maintenance information of the exposure apparatus communicated by the network software executed by the computer.
More preferably, the network software provides, on the display, a user interface connected to an external network outside a factory in which the exposure apparatus is installed to access a maintenance database provided by a vendor or user of the exposure apparatus and allows obtaining information from the database through the external network.
In the exposure apparatus of the present invention, the improved exposure transfer accuracy can be provided by increasing the AF accuracy or the gap setting accuracy.
Further, a device manufacturing method comprises the steps of installing, in a factory, a plurality of semiconductor manufacturing apparatuses for performing various processes, including an exposure apparatus; and manufacturing a semiconductor device using the plurality of semiconductor manufacturing apparatuses, wherein the exposure apparatus comprises a substrate holding apparatus which includes a nonconductive holding section to hold a substrate, and an electrostatic capacitance sensor which measures height-direction information of the substrate held by the substrate holding apparatus, and the holding section includes a conductive member which is electrically grounded.
More preferably, the method further comprises the steps of connecting the plurality of semiconductor manufacturing apparatuses through a local area network, connecting the local area network to an external network outside the factory, acquiring information related to the exposure apparatus from a database on the external network using the local area network and external network, and controlling the exposure apparatus on the basis of the acquired information.
More preferably, the maintenance information of the exposure apparatus is obtained by data communication by accessing, through the external network, a database provided by a vendor or user of the exposure apparatus, or production management is done by data communication with a semiconductor manufacturing factory different from the semiconductor manufacturing factory through the external network.
Further, a semiconductor manufacturing factory comprises a plurality of semiconductor manufacturing apparatuses including an exposure apparatus; a local area network which connects the plurality of semiconductor manufacturing apparatuses; and a gateway which connects the local area network to an external network outside the semiconductor manufacturing factory, wherein information related to at least one of the plurality of semiconductor manufacturing apparatuses can be data-communicated, the exposure apparatus comprises a substrate holding apparatus which includes a nonconductive holding section to hold a substrate, and an electrostatic capacitance sensor which measures height-direction information of the substrate held by the substrate holding apparatus, and the holding section includes a conductive member which is electrically grounded.
Further, a maintenance method for an exposure apparatus, comprises the steps of: causing a vendor or user of the exposure apparatus to provide a maintenance database connected to an external network outside a semiconductor manufacturing factory; connecting the exposure apparatus to a local area network in the factory; and maintaining the exposure apparatus on the basis of information accumulated in the database using the external network and local area network, wherein the exposure apparatus comprises a substrate holding apparatus which includes a nonconductive holding section to hold a substrate, and an electrostatic capacitance sensor which measures height-direction information of the substrate held by the substrate holding apparatus, and the holding section includes a conductive member which is electrically grounded.
Other features and advantages of the present invention will be apparent from the following description taken in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the figures thereof.